Detroit Diesel — Adjust Exhaust Valve Clearance (Cold Engine, Two Valve Head)
Adjustments
From a Detroit Diesel operator's manual — check it applies to your exact model before use.
Before you start
- Do not turn crankshaft in left-hand direction with wrench on front bolt.
Procedure
- Place governor stop lever in stop position.
- Remove valve rocker cover.
- Rotate crankshaft until injector follower is fully depressed on cylinder.
- Loosen exhaust valve rocker arm push rod lock nut.
- Place 0.012 inch feeler gage between valve stem and rocker arm.
- Adjust push rod for smooth pull on feeler gage.
- Remove gage; hold push rod with 5/16 wrench, tighten lock nut with 1/2 wrench.
- Recheck clearance and adjust if necessary.
- Repeat for remaining valves.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 0.012 inch cold
Source: Detroit Diesel operator's manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.